Apparatus for treating ore



E. L. KNAPP ET AL.

APPARATUS FOR TREATING ORE May 25, 1931 Filed June 17, 1936 Patented May 25, 1937 UNITED STATES APPARATUS FOR TREATING one Edwin L. Knapp and Samuel J. Leask,

Anacortes, Wash.

Application June 17, 1936, Serial No. 85,779

Claims.

Our invention relates to an improved apparatus for treating ore for the removal of its metal content, and has especial reference to the treatment of ore containing gold or other noble metals.

In accordance with standard practice it has been the custom to subject the ore to a roasting treatment for the purpose of separating therefrom the refractory products so as to leave the gold or other metal in as nearly a free state as possible. A In connection with this roasting treatment various chemicals have frequently been'used as a further aid in the disintegration of the ore. It has also been proposed to effect some agitation of the ore during the roasting treatment, either in conjunction with the chemical treatment or without it.

However from the point of view of efliciency the heretofore known methods and apparatus have left much to be desired. For instance the treatment has been slow, expensive, has made for considerable loss of the refractory products which are sought to be recovered, and has made necessary various other expensive treatments of the ore following the roasting treatment in order to recover. the gold or other metal. Furthermore, under continuous flow processes as heretofore practiced in known apparatus, it has been impossible to control the speed of travel of the ore through the roaster so as to achieve best results considering the particular ore being treated; and additionally there has been objectionable oxidation of the gold or othennoble metal due to its exposure to the atmosphere to a greater or lesser extent during the roasting treatment.

Our invention therefore has for its primary object to overcome the aforenoted objections and provide a process and apparatus of greatly enhanced efliciency, not only as to the elimination and recovery of the refractory products from the ore, but which will also save time and expense, avoid oxidation of the metal, and enable the speed of flow of the ore through the I roaster to be readily controlled as occasion may require according to the particular ore being treated.

More specifically it is one of the important objects of the invention to provide a process for aid to separation of the refractory products therefrom.

Another object of the invention is to provide a process for the purpose specified which includes the step of subjecting the ore to the action of live steam under pressure in a roaster, retort or the like for the purpose of separating the refractory products therefrom and/or as the vehicle for completely carrying off such refractory products so that same will not condense within the retort or roaster, and can be readily collected in suitable condensers.

Other objects and advantages of the invention will become readily apparent to those skilled in the art as the description proceeds, and reside in certain novel process steps; and in various features of construction, combination and arrangement of the various parts of the apparatus illustrated in the accompanying drawing forming a" part of this specification,

As required by the patent statutes the drawing and this specification deal with what appear to be preferred examples of the inventive concept. However, it is to be understood that the invention is susceptible of other expression within the spirit and scope of the subject matter claimed hereinafter.

In the drawing,

Figure l is a side elevational view, partly in section illustrating a novel continuous flow roaster embodied in the invention;

Figure 2 is a detail view in side elevation of a fluid-receiving ore-discharge-receiving hopper.

associated with the roaster, and which provides a seal for the ore discharge spout thereof to prevent entry of air into the roaster;

Figure3 is a bottom plan view of the hopper shown in Figure ,2. v

Referring specifically to the drawing wherein the same reference characters have been used to designate the same parts in all views, numeral 5 denotes a suitable base which preferably comprehends several laterally spaced and connected I-beams. As shown in Figure 1, the forward end ,of the base 5 supports the furnace 6 which inay beof any suitable construction and adapted for any fuel, although as herein disclosed it is an oil burning furnace having the fuel connection shown at 6.

In carrying out the invention, we provide at the forward or'furnace carrying end of the base 5, an upwardly and rearwardly inclined frame or bed member which may comprise a plurality of laterally spaced and connected I-beams or other supports 1. This frame or bed member is rigidly supported at a predetermined angle to the base by means of upstanding posts or columns 8 at the end of the base; and by intermediate braces such as 9, which may be secured to the base 5 adjacent the rear end of the latter, and connected to the beams 1 of the frame at points between the upper ends of posts 8 and the forward end of the base 5.

Figure 1 illustrates the forward furnace-carrying end of the base 5 as supported upon a horizontal axle or pivot III which is carried by groundsupported blocks or the like III. The rear end of the frame 5 is supported by one or more screw jacks or the like II. Inasmuch as the forward end of the base 5 is supported for vertical pivotal movement about axle I0, it becomes at once apparent that the operation of the jack, or jacks II, enables the inclination of the beam-provided bed 5 to be varied as the result of elevating or loweringthe rear end of the base 5. This is a very important feature of the invention, as will become more clearly apparent as the description proceeds.

The upwardly and rearwardly inclined beamprovided bed I carries the preferably refractory casing I4 leading from the furnace 6. Casing It provides the medial partition l5 preferably formed of overlapping refractory slabs I5. Such partition divides the inclined bed-supported casing lineally into an upper ore-receiving and digesting chamber I2, and a subjacent flue I3 which communicates with the furnace 6 to carry 30 off the products of combustion. The digesting chamber, as will be understood, is heated by the hot gases from the furnace passing up the flue I3, and, as shown, the lower end of the digesting chamber I2 is directly exposed to the heat of the furnace.

The digesting chamber I2 has the ore inlet I6 adjacent the upper end of the refractory bed-carried casing I 4 and the ore outlet 2I at the lower end thereof, as shown.

The ore receiving hopper I E is suitably supported adjacent the upper end of the casing I4 to discharge its ore into the digesting chamber through the inlet I6, and said ore feeding hopper I6 preferably provides a driven feed roll IS in its outlet to assure a continual and even flow of ore to the digesting chamber. Control of the size of the inlet l8 into the digesting chamber I2 is effected by means of the adjustable feed plate or valve I1, it being noted that the feed roll I9 is located at one side of said inlet I6, so as to admit of the plate I1 being actuated inwardly to fully close such inlet I6, if desired. The feed plate or valve I! may be controlled by means of a screw I8 rotatably carried by the bearing lug l6 of hopper I6 and taking in the threaded opening of lug I! of plate II. Numeral 20 designates the drive pulley of the feed roll I9, and it may derive power from any suitable source, not shown.

The lower end of the digesting chamber I2 has its outlet chute 2| discharging into the discharge hopper 22 which has a trough-like bottom 22 within which works the screw conveyor 23 for ejecting the treated ore through the outlet 25. The conveyor has a drive pulley 24 which may be driven by a belt or other source of power, not shown.

In carrying out the invention, we further provide the refractory casing I4, adjacent the furnace 6, with a steam supply pipe 26 discharging into the digesting chamber I2. The steam helps soften the ore and carries off gases and volatile constituents which pass out through the outlet pipe 21 which is located beyond the ore inlet opening I6.

In practicing the process the ore will first be crushed in a suitable crusher, conveyed to a conventional ball or rod mill where it is ground to about eighty or a hundred mesh and discharged into a suitable conveyor which deposits the ground ore into the supply hopper I6. The foregoing being more or less standard practice and forming no part of the present invention, has not been illustrated.

Before admitting ore into the digesting chamber I2, the discharge hopper 22 will be filled with water to immerse the lower end of the ore discharge chute 2|. The furnace 6 will be started and the digesting chamber I2 and its floor provided by the step-like overlapping refractory slabs heated to the proper degree, say, from about 1500 F. to 2500 F., before feed plate I! is retracted and feed roll I9 started to discharge ore into the digesting chamber. However, before we is admitted into the digesting chamber, and while the feed plate or valve I! is still in position to close the digesting chamber inlet I6 live steam under pressure of say from twenty to fifty pounds according to the weight of the refractory elements being given off will be admitted into the digesting chamber through the nozzle 28, so as to drive out the air contained in the digesting chamber through the steam or vapor outlet 21.

When the feed plate or valve I1 is retracted by means of the control screws I8, feed roll I9 discharges ore into the digesting chamber I2 and the ore cascades down the inclined series of steps provided by the heated refractory slabs I5 toward the discharge chute 2|. As pointed out hereinbefore, the speed of travel of the crushed ore toward the outlet chute 2| is governed by the inclination of the series of refractory slabs I5; and such inclination can be varied by adjustment of the jacks I I to raise or lower the rear end of the base 5 about the horizontal axle or front end support I0. Different ore requires different lengths of treatment. Inasmuch as we are able to vary the incline of the series of slag steps I5, we are able to obtain adequate treatment of different ores in a continuous flow digester, such as is illustrated in Figure 1.

The live steam admitted into the digesting chamber through the nozzle 26, not only cooperates with the furnace-supplied heat from slabs I5 in separating the refractory products from the ore, but also serves as the vehicle for gathering up and completely removing such refractory products from the digesting chamber I2 through the steam and vapor outlet 21 which leads to suitable condensers (not shown) for the recovery of such products.

An important point to bear in mind is that inasmuch as the discharge chute 2| is immersed in the water of discharge hopper 22 and the sup ply hopper I6 is kept supplied with ore, it will be impossible for air to find its way into the digesting chamber. Noble metals such as gold are not disintegrated by heat but they will oxidize when heated and cooled in the atmosphere. The elimination and exclusion of air from the digesting chamber I2 is therefore a highly important item.

While various efforts have been made in the past to carry off the refractory products from a roasting chamber by the use of steam vapor as contradistinguished from live steam, such practice has resulted in condensation of such refractory' products and their steam vapor vehicle before same have passed from the roasting chamber. Naturally, this has resulted in loss of refractory products and a general decrease in the efficiency of the treatment as heretofore practiced. Furthermore, the helpful disintegrating action upon the ore by live steam has apparently not been appreciated by those who have preceded us in this art.

By the time the ore reaches the discharge chute 2|, it is in a free milling state and substantially free from refractory elements. Such treated ore having been discharged into the hopper 22 is removed therefrom by means of the driven conveyor 23 from which it may be conducted to a centrifugalizer or amalgamator for final. treatment to extract the metal as usual.

In contradistinction to-- the continuous flow process, as hereinabove described, the ore maybe suitably crushed and ground and deposited in a retort, there to be acted upon by live, steamfizhe retort having first been heated to a predeter mined degree. The sulphur, arsenic, and other I refractory elements of the ore to be carried from the retort by the live steam-and recovered by means, of suitable condensers, as before.

Having thus described our invention, what we claim as new is:

1. Ore treating apparatus comprising a base. a furnace carried thereby, an upwardly "extending inclined casing fixedly carried by said base, said casing providing an ore-digesting chamber having an ore inlet adjacent its upper 'end and an outlet adjacent its lower end, a flue in said casing subjacent to said digesting chamber for heating the latter, said flue having its lower end communicating with the furnace and its upper end communicating with the atmosphere, a refractory partition separating said flue and digesting chamber and forming a top wall of the furnace, and means for varying the inclinationof said base.

extending inclined casing fixedly carried by said base, said casing providing an'ore-digesting chamber having an ore inlet adjacent its upper end and an outlet adjacent its lower end, a flue in said casing subjacent to said digesting chamber, for heating the-latter, said flue having its lowerend communicating with the furnace and its upper end communicating with the atmosphere, a

2. Ore treating apparatus comprising a base, a furnace fixedly carried thereby, an upwardly comprising a base,

a furnace'carried thereby. an upwardly extending inclined casing carried by said base, said casing providing an ore=digesting chamber having an ore inlet adjacent its upper end and an outlet adjacent itslower end, a flue in said casing subjacent to said digesting chamber for heating the latter, said flue having its lower end communicating with the furnace and its upper end communicating with the atmosphere, a refractory partition separating said flue and digesting chamber, a spout extending from said'digestirig chamber outlet, a water containing vessel immersing the outer end of said spout, an ore supg 1 ply hopper adjacent saiddigesting chamber inlet in amanner to cause its contents to substantially seal the same against the entry of air, means for varying the inclination of said casing, a live steam supply means opening into said digesting chamber adjacent itslower end, and an outlet.

for the refractory product-laden steam adjacent I the-upper end of said chamber.

4; Ore treating apparatus. comprising a base,

azfurnace fixedly carried thereby, an upwardly. extending inclined casing fixedly carried by said base,v said casing providing an ore-digesting chamber having an ore inlet adjacent its upper end and an, outlet adjacent its lower end, a flue insaid casing subjacent to said digesting chambar for heating the latter,said flue having its lower end communicating with the furnace, and its upper end communicating withthe atmosphere, a refractory partition separating said flue and digesting chamber, means supporting one end of said base for vertical pivotin .movement, and vertically adjustable supports r the opposite end of said, base whereby the inclination of said casing can be varied .to control the speed of flow of the ore through the digesting chamber.

' 5. Ore treating apparatus comprising a base, a furnace carried thereby, an upwardly extending inclined casing carried by said base, said casing providing anore digesting chamber having an ore inlet adjacent its upper end and an ore outlet adjacent its lower end, a flue intake casing subjacent to said digesting chamber for heating the latter,'said flue having its lower end communicating with the furnace and its upper end communicating with the atmosphere, a refractory" partition separating said flue and digesting chamher and extending into and forming the top wall of the furnace, a steam inlet pipe extending laterally through a wall of the casing into-the ore digesting chamber at its lower end directly above that portion of the partition providing the top wall of the furnace, and a. steam outlet pipe extending laterally through a wall of the casing at the extreme upper end of the digesting chamber.

EDWIN L. KNAPP.

SAMUEL J. LEASK. 

